Just how dangerous is meat and poultry packing?

There's an inside joke among meat industry workers about the risks they face in the slaughter trade: Who is killing whom -- are we killing cattle, or are they killing us on the processing line?

That bit of dark humor was relayed by Jose Gaytan, a former meatpacking worker from Nebraska, who spoke at a telephone press conference held by worker advocates to discuss a report released Wednesday from the Government Accountability Office (GAO), which found illness and injury rates on the decline, but also underreported.

Gaytan lasted three years on the job before the impact on his health prevented him from continuing. "After hours, my hands would swell up, and the pain never went away," he said. "I saw a lot of injuries from the work speed. Twice I saw saw operators cut off their fingers."

Evaluations by the Centers for Disease Control and Prevention (CDC) and academic studies found the nation's estimated 526,000 meat and poultry processing workers face hazards including tasks involving repetitive motion and prolonged standing linked to musculoskeletal disorders, exposure to chemicals and pathogens, and traumatic injuries from machines and tools, the GAO said in its report.

The drive to maintain or increase production "pushes workers beyond their limits," said Oliver Gottfried, senior advocacy adviser at Oxfam America, which recently issued a report that found the nation's roughly 250,000 poultry workers are routinely denied bathroom breaks.

The GAO, an independent, nonpartisan agency, listed multiple challenges in gathering data, including workers fearful for their jobs reluctant to report injuries and illness, and employers financially motivated to undercount those instances.

One former poultry plant employee offered anecdotal evidence of the former, saying he lost his job after injuring his right hand and shoulder at a Minnesota poultry processing plant.

"I went to a doctor, who said you cannot do the same level of work you do right now, and he gave me a note to take to the company," Omar Hassan told the advocacy call. "They told me you cannot bring us any note from a medical doctor. I tried talking them into placing me on light duty, and they said 'no, we'll let you go.' They fired me for that."

Additionally, the GAO noted the Department of Labor collects detailed data only for injuries and illnesses that result in workers taking time off work. It doesn't compile data on meat and poultry sanitation workers who might not be classified in the industry if they work for outside contractors.

"In our outreach around the Southeast, we found a number of plants that use labor contractors as an intermediary to find workers and distance themselves from their own workforce," said Sarah Rich, a staff attorney at the Southern Poverty Law Center. "The contracting model is becoming more and more widespread through American economy, and the poultry industry is no different."

It employs "a very vulnerable workforce, including a lot of immigrants," Rich added, echoing the GAO's findings that immigrants make up about 30 percent of the workforce.

Like its findings in 2005, the GAO's latest report indicates meat and poultry processing workers "still face hazardous working conditions that put their health in jeopardy," Senator Patty Murray, D-Washington, told the telephone conference. In addition, some processors "might actually discourage their workers from reporting injuries," she added.

While higher than for manufacturing overall, rates of illness and injury in meat and poultry processing fell to an estimated 5.7 cases for every 100 full-time workers in 2013 from 9.8 in 2004, according to the GAO, which compiled its report at the request of three lawmakers, including Murray.

Trade groups touted the downward trend, which the National Chicken Council cited as evidence of ongoing improvement in worker safety, and the North American Meat Institute said the industry is "safer than ever."

Other advocates pointed out the GAO had cast doubt on its estimates and dismissed industry claims.

"We should have no confidence about industry's assertions about their injury rates,"Celeste Monforton, an expert in occupational safety and health, said during the call. Administrations of first aid do not have to be reported to regulators, and injured workers are often given aspirin or hot compresses and "sent back to the processing line," said Monforton, a professorial lecturer at George Washington University's Milken Institute School of Public Health.

For instance, after a new regulation increased the level of reporting required by companies, a look at Tyson Foods (TSN), the nation's biggest poultry processor, found it had reported 34 instances of amputations or hospitalizations in a nine-month period starting Jan. 1, 2015, a figure that excludes 10 states in which Tyson operates but that run their own OSHA programs.

Tyson didn't dispute this, but it did defend its safety efforts on behalf of its 113,000 workers, saying the company employs nearly 500 health and safety professionals and had cut workers' illness and injury rates by 12 percent over the past two years.

"If a team member gets hurt on the job, we require them to report it, regardless of how minor they believe it to be," said Gary Mickelson, a Tyson spokesman. "We work to prevent injuries and illnesses. But if they happen, we want them detected early so they can be immediately addressed."